Yann Bezin, Head of Research – Institute of Railway Research | University of Huddersfield
Designing future turnouts – where research capabilities meet industry needs
Railway switches and crossings (S&C) are the most costly items for railway infrastructure managers. In the UK over 20% of the planned maintenance and renewal budget for 201419 is taken by S&C despite the fact that they only represent a small proportion of the network in terms of kminstallation. They are complicated and expensive assets, representing a bottle neck with potential for costly traffic disruptions while attracting a large proportion of the networks failures (e.g. Point Operating Equipment POE related).
Recent European projects (e.g. Innotrack, Sustrail, Drail, Capacity4Rail) and the new H2020/Shift2Rail opportunities for funding are enabling industry and research institutes to work together with infrastructure managers and suppliers to help rethink and redesign a technology which in some aspects remains truly embedded in the middle of last century. What was then a satisfactory design is now being proven beyond its intended design capacity, with ever increasing loads, traffic speed and frequency; while at the same time the window for maintenance and intervention is being drastically narrowed.
One fundamental aspect emerging from these previous research programmes is that a lot of the observed failures surrounding S&C have their root cause explained by the discontinuities experienced by the vehicle at S&C. The nature of these is related to the varying geometrical interface between the vehicle wheels and the guiding rails (e.g. load transfer between stock and switch rails), as well as the uneven vertical support offered to the vehicle through the S&C (e.g. uneven loading of long bearers, increased bending stiffness of cast crossings).
A large number of reliability issues find their source in the physical vibrations and dynamically amplified loads occurring because of these two facts, this includes some of the gradual deterioration experienced by POE. Research institutes, including the Institute of Railway Research at the University of Huddersfield, have helped develop advanced simulation tools capable of confidently predicting these phenomena and assess contributory factors to degradation modes as well as iteratively work on remedial actions. These might either be small step changes to existing designs or they might be radical concept changes, covering short, medium and long term vision for 2050 railways in Europe.
The author will summarise some of the outcome of recent EU projects, give examples of were simulation technology might be used to assess future improvements and radical changes, as well as opportunities for validating these and other wheelrail interface research projects using advanced testing techniques.